Have you looked at limiting the amount of data that you sync with the device/PC? In ActiveSync you can change the time frame for 'Calendar' items that you sync. Then the data remains on your PC and you are not clogging up the device with excess data. If you are not familiar with this setting, connect your device to your PC and let ActiveSync run. When ActiveSync shows finished on the PC, go there to choose View > Details, then double click on 'Calendar' there and you will see the settings options for limiting the time frame of data that you are syncing.